Stop in for a cup of coffee

71GSSDemon said
Question for all you smart people out there......How to calculate the compression ratio of an engine that is complete? I know compression test gives you psi, but what about the overall ratio?

Air pressure is 14.7 psi at sea level. Therefore, you divide the total measured pressure by 14.7 to get the absolute compression ratio.

147 psi would equal 10.1 compression ratio.